how do i save my selfmade favorit color ramp gradient in node editor?
Depending on how often you want to use your gradients, you can save them in two ways.

Both methods start by grouping your ColorRamp node. After you have set the gradient as you want, select the color ramp node and press CrtlG that will create a node group only containing the color ramp node. Rename the new node group, in the properties region N so you can find the gradient later.



If you use the gradients a lot, just save the node groups in your start up file.

The second method is to have a file of node assets, and when you want a gradient Append the node group from the file, with ShiftF1.